The fuel quantity that is delivered to an internal combustion engine may be determined by an electronic governor system. The electronic governor system determines the amount of fuel that should be injected by each fuel injector into the engine. The governor system then sends a fuel command to the fuel injectors to deliver the fuel. In typical electronic governor systems the same fuel command is sent to each fuel injector. However, due to variances between each fuel injector, the same fuel command does not inherently result in the same quantity of fuel being delivered to the engine by each injector. The result of fuel variations is an incorrect engine speed. Under most of the operating range of an engine, the variances between each fuel injector are not significantly noticeable. However, at low engine speeds, especially when the engine is idling, small variances in fuel quantity can result in proportionally large variances in resultant engine speed. For example, an engine may be running at 3000 revolutions per minute (rpm) and each fuel injector commanded to deliver 200 mm of fuel to maintain the speed. If a fuel injector is off by plus or minus 2 mm of fuel, the resulting engine speed will not be noticeably effected. However, if an engine is idling at 500 rpm and a fuel injector is commanded to deliver 8 mm of fuel to maintain the speed, a variance of 2 mm of fuel will make a significant impact on the resultant engine speed. Delivering an incorrect fuel quantity when an engine is running at low speeds will result in the engine not running smoothly.
Some systems create a calibration curve for each fuel injector and download the curve to an EPROM mounted on the injector. However flow rates for each fuel injector may change during the operation of the engine, rendering a static calibration curve inaccurate after a short period of time.
The present invention is directed to overcoming one or more of the problems set forth above.